IN THE NAME OF ALLAH

The Skull 22 bones joined together by sutures Cranial bones surround cranial cavity 8 bones Facial bones support teeth & form nasal cavity & orbit 14 bones

Frontal Bone Forms forehead and part of the roof of the cranium Forms roof of the orbit Contains frontal sinus

Parietal Bone Forms cranial roof and part of its lateral walls Bordered by 4 sutures coronal, sagittal, lambdoid and squamous Marked by temporal lines of temporalis muscle Temporal lines

Temporal Bone Forms lateral wall & part of floor of cranial cavity squamous part zygomatic process mandibular fossa & TMJ tympanic part external auditory meatus styloid process mastoid part mastoid process mastoid notch digastric muscle

Petrous Portion of Temporal Bone Forms part of cranial floor separates middle from posterior cranial fossa Houses middle and inner ear cavities

Openings in Temporal Bone

Occipital Bone Foramen magnum holds spinal cord occipital condyles

Sphenoid Bone Lesser wing Greater wing Body of sphenoid Medial and lateral pterygoid processes

Sphenoid Bone Body of the sphenoid Lesser wing sella turcica contains deep pit (hypophyseal fossa) houses pituitary gland Lesser wing optic foramen contains optic nerve & ophthalmic a.

Sphenoid Bone Sphenoid sinus

Ethmoid Bone Between the orbital cavities Forms lateral walls and roof of nasal cavity Cribriform plate & crista galli Ethmoid air cells form ethmoid sinus Perpendicular plate forms part of nasal septum Concha or turbinates on lateral wall

Ethmoid Bone Superior & middle concha Perpendicular plate of nasal septum

Maxillary Bones Forms upper jaw Forms inferomedial wall of orbit alveolar processes are bony points between teeth alveolar sockets hold teeth Forms inferomedial wall of orbit infraorbital foramen Forms anterior 2/3’s of hard palate incisive foramen cleft palate

Locations of Paranasal Sinuses Frontal Ethmoid Maxillary Sphenoid Maxillary sinus fills maxillae bone Other bones containing sinuses are frontal, ethmoid & sphenoid.

Palatine Bones L-shaped bone Posterior 1/3 of the hard palate Part of lateral nasal wall Part of the orbital floor

Zygomatic Bones Forms angles of the cheekbones and part of lateral orbital wall Zygomatic arch is formed from zygomatic bone and zygomatic process of temporal bone

Lacrimal Bones Form part of medial wall of each orbit Lacrimal fossa houses lacrimal sac in life

Nasal Bones Forms bridge of nose and supports cartilages of nose Often fractured by blow to the nose

Inferior Nasal Conchae A separate bone

Vomer Inferior half of the nasal septum Supports cartilage of nasal septum

Mandible Only bone of the skull that can move Holds the lower teeth jaw joint formed between mandibular fossa of temporal bone & condyloid process Holds the lower teeth Attachment of muscles of mastication temporalis muscle onto coronoid process masseter muscle onto angle of mandible Mandibular foramen Mental foramen

Bones Associated With the Skull Auditory ossicles malleus incus stapes Hyoid bone suspended from styloid process of skull by stylohyoid muscle and ligament greater & lesser cornua

Major Skull Cavities Cranial cavity holds brain Orbit contains eyeball & extraocular muscles Ethmoid sinus Nasal cavity Maxillary sinus Oral cavity

Cranial Fossa 3 basins that comprise the cranial floor or base Anterior cranial fossa Middle cranial fossa Posterior cranial fossa

The Skull in Infancy & Childhood Spaces between unfused skull bones called fontanelles filled with fibrous membrane allow shifting of bones during birth & growth of brain in infancy 2 frontalle bones fuse by age six metopic suture

Norma Verticalis

Norma Frontalis

Norma Occipitalis

Norma Lateralis

Norma Basalis